Method and apparatus for manufacturing a stator of a dynamo-electric machine

ABSTRACT

The method and apparatus comprise the following features: —forming coil members ( 21 ) by bending an electric conductor ( 20 ) externally coated with an outer insulation ( 20 ′); wherein the bending is made at predetermined lengths from a reference position ( 16 ′), and wherein each one of the coil members ( 21 ), when formed, comprises at least one head portion ( 21 ′) and leg portions ( 21 ″) extending from said at least one head portion ( 21 ′); —feeding the electric conductor ( 20 ) to accomplish the bending; —cutting the electric conductor ( 20 ) to detach a formed coil member ( 21 ) from said electric conductor ( 20 ); —inserting the leg portions ( 21 ″) of the coil members ( 21 ) into slots of the stator, so that parts of said leg portions ( 21 ″) extend from one end of the stator and the head portions ( 21 ′) extend from an opposite end of the stator; —arranging at least one laser beam ( 13′   a,    13′   b ) to remove the insulation ( 20 ′) from predetermined areas ( 20   a,    20   b ) of the electric conductor ( 20 ); —radiating the surface of the electric conductor ( 20 ) with said at least one laser beam ( 13′   a,    13′   b ) situated at a predetermined position (IP,  2 P) with respect to the reference position ( 16 ′) along the length of the electric conductor ( 20 ) being fed, and at a predetermined stage of the bending of a coil member ( 20 ).

TECHNICAL FIELD

The present invention relates to a method and apparatus formanufacturing a stator of a dynamo-electric machine, and moreparticularly, to a method and apparatus for removing insulation materialfrom an electric conductor used for forming coil members of a coilassembly of the stator.

BACKGROUND ART

Coil members, such as U-shaped members, also referred to as hairpins,require that the insulation covering be removed from the conductive coresurrounding the electric conductor. This allows joining of uninsulatedcores of the electric conductor by means of welding operations, or otherjoining techniques.

Patent publication WO 2012/156066 discloses methods and apparatuses forforming the coil members like hairpins by bending the end of an electricconductor fed from a supply reel. A formed coil member has ends, whichare cut to free the formed coil member from the electric conductorsupplied to form the coil member.

Welding machines for joining the ends of hairpins have been described inpatent publication WO 2012/119691.

A typical manufacturing cycle for producing a finished stator core,wound with coil members like hairpins, generally includes:

-   -   forming the coil members from an electric conductor,    -   assembling multiple coil members to form the complete coil        assembly of the stator core,    -   inserting the coil assembly into the stator core by inserting        the legs of the coil members into the slots of the stator core,    -   twisting the portions of the legs of the coil members that        protrude from the stator to bring such portions into welding        positions,    -   welding said portions.

Removing insulation from the electric conductor at the forming stage ofthe coils members simplifies and optimizes successive welding operationsof the portions where the insulation has been removed.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a laser solution forremoving insulation from portions of an electric conductor, which is fedto a bending unit where a coil member is formed.

It is further object of the invention to accomplish the removing of theinsulation during the bending operations to form the coil member.

According to the present invention, these and other objects are achievedthrough a method and an apparatus as set out in the appended independentclaims.

It is to be understood that the appended claims are an integral part ofthe technical teachings provided in the following detailed descriptionof the present invention. In particular, the dependent claims appendedhereto define some exemplary embodiments of the present invention, whichinclude some optional technical features.

Further features and advantages of the present invention will becomeapparent in the light of the following detailed description providedmerely by way of non-limiting example with particular reference to theannexed drawings, which will be briefly described below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevation view of an apparatus made in accordance with anexemplary embodiment of the present invention, according to a schematicrepresentation thereof.

FIG. 1a is a view seen in the direction indicated by arrows 1 a-1 a ofan electric conductor.

FIG. 2 is a plan view of a coil member manufactured according to theprinciples of the invention.

FIG. 3 is a partial sectional view, as seen from the direction of thearrows 3-3 of FIG. 1.

FIG. 4 is a partial sectional view, as seen from the direction of thearrows 4-4 of FIG. 1.

FIG. 5 is an enlarged partial view of portion 5 of FIG. 1.

FIG. 6 is a partial sectional view from the direction of the arrows 6-6of FIG. 5.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 schematically shows an exemplary embodiment of the presentinvention, wherein a supply reel 10 is rotated to feed the electricconductor 20 employed for forming a U-shaped member, also referred to ashairpin, shown in FIG. 2.

As is known in the industry, the electric conductor 20 has a conductiveinner core surrounded by an insulation 20′, which is electricallyinsulating and externally coats the core.

The electric conductor 20 leaving the supply reel 10 passes through astraightening unit 11 (which may include, for example, rollers) forremoving any bends or folds that might be present in the electricconductor 20. In this way, the electric conductor 20 is accuratelyaligned for the next operations that will have to be carried out.

Subsequently, the electric conductor 20 passes through a laser unit 13for removal of the insulation 20′. More particularly, predeterminedlengths L of insulation 20′ are removed from the electric conductor 20at predetermined positions along said electric conductor 20, as shown inFIGS. 1a , 3 and 4. With particular reference to FIGS. 1a, 20a and 20bdesignate removal areas that represent those portions or areas of theconductor 20 where the predetermined lengths L of insulation 20′ havebeen removed.

With reference to FIGS. 1, 3 and 4, laser unit 13 is provided with afirst laser source 13 a configured for generating a first laser beam13′a capable of scanning the surface of the electric conductor 20 in afirst position, indicated by arrow 1P. Preferably, the laser unit 13 isalso provided with a second laser source 13 b configured for configuredfor generating a second laser beam 13′b capable of scanning the surfaceof the electric conductor 20 in a second position 2P. Positions 1P and2P are fixed with respect to an absolute reference; in other words, theyrepresent positions through which the electric conductor 20 passes as itis fed from supply reel 10.

According to one embodiment of the invention, each of laser sources 13 aand 13 b generates a pulsed laser beam 13′a, 13′b having a spotconfiguration radiated on a zone of the surface of the electricconductor 20. Operationally there are multiple zones which are radiatedby the spot configuration and which make the removal areas 20 a and 20 bof the electric conductor 20 where insulation removal occurs. The laserbeams 13′a and 13′b move with respect to the electric conductor 20 inorder to achieve a succession of radiations of the spot configuration onthe above-mentioned multiple zones. In other words, the laser beams 13′aand 13′b scan the removal areas 20 a and 20 b by means of the spotconfiguration of the laser beams 13′a and 13′b.

More precisely, the scanning of a laser beams 13′a and 13′b consists ofthe spot configuration moving along predetermined trajectories of thesurface of the electric conductor 20, which result in removal areas 20 aand 20 b.

The predetermined trajectories can be multiple linear paths adjacent toeach other, on which the spot configuration moves in succession. Thisresults in the spot configuration moving in forward and reversedirections along the linear paths, one after the other. Adjacent linearpaths can also be partially superimposed to ensure sufficient coverageor radiation of the removal areas 20 a and 20 by the laser beam.

When the spot configuration is radiating a zone of the trajectories, theheating energy of the laser beam causes the underlying insulation 20′ tomelt into a gaseous state. This results in the removal of the insulation20′ to expose the conductive core of the electric conductor 20 in theremoval areas 20 a and 20 b.

Each laser source 13 a, 13 b can be provided with a reflecting device ormirror for moving the laser beam 13′a, 13′b along the trajectoriesrequired for removing the insulation from the removal areas 20 a and 20b. The reflecting devices or mirrors can be controlled by respectivecontrollers 14.

In particular, each controller 14 can cause a spot configuration toradiate the surface of the electrical conductor 20 at predeterminedpositions and at a certain time. In addition, the controllers 14 cancontrol the speed of the spot configuration, and hence the speed atwhich the surface of the electric conductor 20 is scanned by the laserbeams 13′a and 13′b.

This ultimately results in controlling the speed of movement of the spotconfiguration along the predetermined trajectories of the surface of theelectric conductor 20 where the insulation 20′ needs to be removed.

Each laser source 13 a and 13 b is characterized by having an area rangewhere the predetermined trajectories are contained. The differentpositions of the spot configuration for the scanning fall within thisarea range. The area ranges of the laser beams 13 a and 13 b need tomatch the removal areas 20 a and 20 b to remove the insulation.

These area ranges can be increased by changing the laser sources 13 a,13 b, or by moving the sources farther from electric conductor 20.Furthermore, the area ranges can be located at a different position 1P,2P along the electric conductor by moving the laser sources 13 a, 13 bparallel to the feeding direction of the electric conductor, through theuse of movement devices 19.

The position of the area ranges needs to be predetermined with respectto spatial reference axes, like the central axis 20′ of the section ofelectrical conductor 20 (see FIGS. 3 and 4), and the plane 16′ where thecutting blade of cutting unit 16 cuts through the section of theelectric conductor. This corresponds to the spot configuration radiatingat a predetermined distance along the electric conductor from plane 16′.

The controllers 14 of the reflecting devices or mirrors of the lasersources 13 a and 13 b obtain the predetermined values of the positionand speed of the spot configuration with respect to the above-mentionedreferences.

FIGS. 3 and 4 show the angular position of the laser sources 13 a and 13b with respect to the electric conductor 20. Each laser source 13 a and13 b is located in an angular position wherein a laser beam 13′a and13′b being emitted can radiate a respective width side and a respectiveheight side of the cross-section of the electric conductor, as shown inFIGS. 3 and 4. More particularly, the laser beam 13′a emitted by thelaser source 13 a can scan the width side W1 and the height side H1,whilst the laser beam 13′b of the laser source 13 b can scan the widthside W2 and the height side H2, with reference to the area rangesmentioned in the foregoing.

Guide passages 12 a, 12 b and 12 c maintain the electric conductoraligned with the laser beams 13′a, 13′b during the scanning, when theelectric conductor 20 moves towards the bending unit 17, as shown inFIG. 1.

Feeding unit 15 causes the electric conductor to be drawn from supplyreel 10 and to be pushed towards the bending unit 17. This results inrotating the supply reel 10 to unreel the electrical conductor 20 andcause it to advance towards the bending unit 17. During the thrustexerted by the feeding unit 15, the electric conductor 20 moves withrespect to the bending tool 18 and the cutting tool 16, as described inpatent publication WO 2012/156066, in order to form a coil member. Inparticular, the electric conductor 20 is moved and made to pass throughthe bending tool 18 for a series of predetermined lengths of the variousbending stages required for forming the configuration of the coilmember. The predetermined lengths can be measured from the referenceplane 16′ of the cutting tool 16, or from other reference positionsrelated to the bending stages for forming the coil member, as describedin patent publication WO2012/156066.

At the end of these movements, the cutting tool 16 cuts through thesection of the electric conductor 20 to detach the formed coil member.In particular, the cutting can occur at the middle of the predeterminedlength L of the portions 20 a and 20 b of the electrical conductor,where the insulation 20′ has been removed.

In order to increase the rate of producing coil members by means ofbending unit 17, laser unit 13 can remove the insulation during thebending stages required for forming the coil members. This requiresremoving the insulation 20′ during the feeding movements in direction Fof electric conductor 20 towards the bending unit 17, and thereforeremoval of insulation 20′ from the electric conductor 20 when it is bentby the bending unit 17 to form the coil member.

To achieve this, the feeding movement of electric conductor 20 towardsthe bending unit 17 needs to be synchronized with the removal ofinsulation 20′ occurring by means of laser beams 13′a and 13′b. Inparticular, the scanning of laser beams 13′a and 13′b needs to besynchronized with the feeding of electric conductor 20 towards thebending unit 17. This requires the spot configuration of the laser beams13′a and 13′b to move along the scanning trajectories when the electricconductor 20 is moved towards the bending unit 17.

Analytically, this requires satisfying the following algebraic sum:

Vscan=Vscan stat+Vfeed bending, where:

-   -   Vscan is the speed of the spot configuration during the scanning        with respect to a stationary reference, like plane 16′, when the        electric conductor 20 is moving towards the bending unit 17;    -   Vscan stat is the speed of the spot configuration during the        scanning with respect to the electric conductor, i.e. the        scanning speed when the electric conductor 20 is stationary,        which corresponds to a scanning speed previously determined for        removing the insulation 20′ when the electric conductor 20 is        stationary;    -   V feed bending is the speed of the electric conductor 20 during        the various feeding stages of the bending operations performed        by bending unit 17.

The sum of the speeds needs to be algebraic due to the sign of the Vscanstat parameter, which may be either positive or negative depending onwhether the direction of movement of the spot configuration during thescanning is concurrent or opposite to the feeding direction of theelectric conductor 20. Therefore, a change in the sign of the Vscan statparameter dependent on the scanning trajectory occurs at a certaininstant of the insulation removal stage. The negative sign will beassociated with a movement of the spot configuration in a directionopposite to direction F for the feeding of electric conductor 20.

The positions of laser sources 13 a and 13 b along the electricconductor 20 can be chosen to correspond to a predetermined distancefrom reference plane 16′ or another reference of the bending unit 17;therefore, the positions of laser sources 13 a and 13 b along theelectric conductor 20 can be selected as a function of the position inwhich the bending operations occur. This determines the position of thearea ranges of the scanning of laser beams 13′a and 13′b, so that thescanning process can occur in a predetermined position 1P, 2P withrespect to a predetermined stage of the bending or cutting process.

In this way, complete removal of the insulation 20′ from the removalareas 20 a and 20 b can be achieved. Furthermore, this will guaranteethat removal areas 20 a and 20 b will be positioned at the referenceplane 16′ for cutting during a required stage of the bending process.

For example, this will ensure that cutting will occur in the middle ofremoval areas 20 a and 20 b to form exposed ends 21 a and 21 b of theleg portions 21″ of coil member 21 shown in FIG. 2.

The positions 1P and 2P of laser sources 13 a and 13 b along theelectric conductor 20 from reference plane 16′ can correspond to amultiple integer n of the lengths of electric conductor 20 required toform a complete coil member. For example, an integer number multipliedby the length of electric conductor 20 required to form the coil member21 of FIG. 2, i.e. the length from the cut part of the exposed end 21 ato the cut part of the exposed end 21 b. This can guarantee that thebending stages and the cutting will occur for predetermined feed lengthsof the electric conductor 20 in direction F with respect to a referenceposition of the laser beams 13′a and 13′b or of the laser sources 13 aand 13 b.

The laser unit 15 can determine the position of the points of origin forthe movement of laser beams 13′a and 13′b with respect to the cuttingposition and the bending position of tool 18. Scanning can start whenthe laser beams 13′a and 13′b are aligned with the origin to fulfill aposition function between the position of removal of the insulationalong the electric conductor and the bending for forming the coilmember, and the cutting of the coil member.

This position function guarantees that removal of insulation 20′ occursduring a predetermined stage of bending, for example when bending isoccurring for a head of the hairpin 21′, which can be the slowest of thebending stages. This will give adequate time for the insulation removaloperation to occur. In other words, this will guarantee that thescanning speed will be sufficient for completing the removal of theinsulation 20′ before the required removal areas 20 a, 20 b of theelectric conductor 20 are fed past the area ranges of the laser beams.

According to an alternative embodiment, the laser sources 13 a and 13 bmove in the direction F synchronized with the feeding speed of theelectric conductor 20. In this situation, the position of the laserbeams 13′a and 13′b will at any given instant correspond to apredetermined position with respect to the reference position 16′ duringthe movement of the laser sources 13 a and 13 b caused by movementdevices 19, as shown in FIG. 1.

Therefore, the predetermined position of the laser beams 13′a and 13′bwill change not only for the scanning movement, but also with anadditional movement component, which will be due to the movement of thelaser sources 13 a and 13 b synchronized with the feeding of theelectric conductor 20. In this alternative embodiment, the movement ofthe laser sources 13 a and 13 b can occur during a predetermined bendingstage, e.g. during the bending of the hairpin head. This alternativeembodiment can offer the advantage of further reducing the timenecessary for removing the insulation while feeding the electricconductor 20.

With reference to FIGS. 5 and 6, feeding unit 15 is provided with twoclamp units 30 and 31 for clamping the electric conductor 20. Clampunits 30 and 31 are substantially identical, and therefore the detaileddescription will be limited to clamp unit 30.

The clamp unit 30 comprises a pair of clamps 30 a and 30 b, as shown inFIGS. 5 and 6, which can hold the electric conductor 20, by movingclamps 30 a and 30 b towards each other in direction C. An oppositemovement of the clamps, i.e. away from each other, will release theelectric conductor 20.

The movement of an arm 32 achieves the movement of clamp 30 a forholding and releasing the electric conductor 20. More particularly, arm32 is hinged to clamp 30 a portion 33 (see FIG. 6), and arm 32 isprovided with an enlarged portion 34 located on shaft 35. Shaft 35 issplined to make the enlarged portion 34 to rotate, and to allowmovements in two opposite directions F and F′ of enlarged portion 34.Movements of enlarged portion 34 in directions F and F′ causecorresponding movements of clamp unit 30 in directions F and F′.Rotation of enlarged portion 34 in directions R and R′, by rotatingshaft 35, respectively cause clamping of electric conductor 20 bymovement of clamp 30 a in direction C, or releasing 20 of electricconductor 20 by movement of clamp 30 a in direction opposite to C.

Programmable motor belt transmission 40 is provided for rotating shaft35.

When clamp unit 30 holds electric conductor 20 and moves in direction F,a predetermined length of electric conductor 20 is fed to the bendingunit 17 from supply reel 10. With clamp 30 open and following a movementin direction F′, clamp unit 30 is repositioned along electric conductor20 at the beginning of the stroke in direction F for feeding apredetermined length of electric conductor 20.

Clamp unit 30 can be moved in directions F and F′ by moving trolley 36on guide bars 36′. Clamps 30 a and 30 b are assembled on trolley 36, asshown in FIGS. 5 and 6. Trolley 36 is engaged with screw bar 37. Screwbar 37 is rotated by motor belt transmission 41, shown in FIG. 6, toaccomplish movement of trolley 36 in directions F and F′. The motortransmission 41 is provided with an encoder 39 for transmitting theposition of clamp unit 30 during the movements in direction F and F′.

As shown in FIGS. 5 and 6, clamp unit 31 is provided with parts similarto those of clamp unit 30. However, the trolley of clamp unit 31, liketrolley 36, is engaged on a portion 37′ of screw bar 37, having the samepitch but opposite threading to where trolley 36 of clamp unit 30 isengaged on screw bar 37. In this way, when clamp unit 30 moves in one ofdirections F and F′, clamp unit 31 moves oppositely for same quantitiesin the other of directions F and F′. More particularly, clamp units 30and 31 move simultaneously and symmetrically with respect to mid axis37″ of screw bar 37 (see FIG. 5) in opposite directions F and F′, andwith respect to each other. Clamp units 30 and 31 are closed when movingin direction F to feed the electric conductor 20, and open when movingin direction F′ for repositioning. In other words, clamp unit 30 drawsand pushes electrical conductor 20 when clamp unit 31 is open and movingin direction F′. Similarly, clamp unit 31 draws and pushes electricalconductor 20 when clamp unit 30 is open and moving in direction F′. Thiscombination of movements, and the alternative opening and closing of theclamp units reduces dead times, when neither pushing nor pulling ofelectric conductor 20 occurs.

The enlarged portion (not shown) of the lever 32′ of clamp unit 31 issimilar to the enlarged portion 34 of lever 32, although the enlargedportion of lever 32′ will be mounted on the splines of shaft 35 with anangular shift with respect to the position of enlarged portion 34. Thus,clamp unit 30 can be opened when clamp unit 31 is closed, and clamp unit30 can be closed when clamp unit 31 is open.

Controllers 50 are configured to guarantee the sequence and values ofthe movements of clamp units 30 and 31, and the open and closedconditions of clamp units 30 and 31 at specific times. The objective ofthe controllers can consist of feeding predetermined lengths ofconductor with respect to reference plane 16′ and to other referencepositions of the bending process. Controllers 50 can accomplish this byactivating and controlling motor transmission 40 and motor transmission41 according to programmed functions, which can be the feed displacementof electric conductor 20 for the various stages of bending, and thepositioning of the clamp units 30 and 31 along electric conductor 20.

Furthermore, the feedback of encoder 39, which represents the length ofconductor being fed, can be used in closed loop feedback by controllers50 to control motor transmission 40. The programmed functions can bespecific for the electric conductor 20 and the coil member that needs tobe formed, and can be set in controllers 50 when setting the apparatusfor the coil member to be formed.

With reference to the synchronization of the application of the laserbeams 13′a and 13′b on electric conductor 20 and the feeding of electricconductor 20, as described in the foregoing, controller 50 transfersencoder data along signal lines 50′ to controllers 14. This datacorresponds to lengths of electric conductor being fed to the bendingunit 17 by unit 15. Controllers 14 can convert the encoder data into thespeed parameter Vfeed bending described in the foregoing with referenceto the speed formula, and thus the controllers 14 can calculate theVscan parameter for controlling the reflecting devices or mirror toachieve synchronization.

In other words, controllers 50 can act as a master control forcontrolling the feed of lengths of the electric conductor 20 in thevarious stages of the bending of the coil member 21, and supplying theelectric conductor position information to controller 14 for thesynchronization of the scanning with the feeding on behalf of unit 15.

When a coil member having a different configuration needs to beprocessed, the length of the coil member between the cut ends maychange. In this situation, the reflecting devices or mirrors of lasersources need to accomplish scanning of the electric conductor 20 at adifferent distance from reference plane 16′, i.e. in different positions1P and 2P. In this situation, controller 50 will be programmed to have adifferent sequence of the feed of lengths of the electric conductor 20for the various stages of the bending. In addition, the referencepositions or points of origin where the laser beams 13′a and 13′b startthe scanning and the position of the area ranges may need to berepositioned to ensure that the required lengths of insulation 20′ willbe removed from removal areas 20 a and 20 b, in a situation whereremoval areas 20 a and 20 b will need to be achieved at the newdistances from reference planes for the bending or the cutting.

To optimize the removal of insulation 20′ from the electric conductor20, the laser beam will be chosen to have a wavelength that ensures highabsorption of the radiation energy by the insulation 20′, and highreflection of the radiation energy by the core of the electric conductor20.

In addition, the pulses of the pulsed laser beam can be chosen tooptimize removal as a function of the feed speed of the electricalconductor 20. The power of the heating radiation can be selected as afunction of the area that needs to be scanned and of the time availablefor the scanning.

An alternative to using pulsed radiation and scanning can be a VCSELlaser beam, which is an abbreviation for Vertical Cavity SurfaceEmitting Laser. The VCSEL beam will need to be positioned at apredetermined position from the reference planes for bending or cutting.The VCSEL beam can be activated by a respective control synchronizedwith the feeding, at a predetermined stage of the bending process.

Naturally, without prejudice to the principle of the invention, theembodiments and the implementation details may be extensively variedfrom those described and illustrated herein by way of non-limitingexample, without however departing from the scope of the presentinvention as set out in the appended claims.

1. A method for manufacturing a stator of a dynamo-electric machine,said method comprising: forming coil members by bending an electricconductor externally coated with an outer insulation, wherein thebending is made at predetermined lengths from a reference position, andwherein each one of the coil members, when formed, comprises at leastone head portion and leg portions extending from said at least one headportion; feeding the electric conductor to accomplish the bending;arranging at least one laser beam to remove the insulation frompredetermined areas of the electric conductor; irradiating the surfaceof the electric conductor with said at least one laser beam situated ata predetermined position with respect to the reference position alongthe length of the electric conductor being fed, and at a predeterminedstage of the bending of a coil member; cutting the electric conductor todetach a formed coil member from said electric conductor; and insertingthe leg portions of the coil members into slots of the stator, so thatthe parts of said leg portions extend from one end of the stator and thehead portions extend from an opposite end of the stator.
 2. The methodaccording to claim 1, further comprising: speed radiating said at leastone laser beam on multiple zones of the predetermined areas by movingsaid at least one laser beam with a predetermined movement; andsynchronizing the movement of said at least one laser beam with themovement of the feeding of the electric conductor.
 3. The methodaccording to claim 2, wherein the synchronization occurs by summing thespeed of movement of at least one laser beam to the speed of themovement of the feeding of the electric conductor.
 4. The methodaccording to claim 1, further comprising positioning said at least onelaser beam at a predetermined distance from the reference position,wherein the predetermined distance is an integer multiple of the lengthof the electric conductor required to form a coil member.
 5. The methodaccording to claim 1, further comprising radiating two laser beams alongthe electric conductor, wherein a width side and a height side of theelectric conductor are radiated by one of the laser beams, and a secondwidth side and a second height side of the electric conductor areradiated by the other one of said laser beams.
 6. The method accordingto claim 1, further comprising receiving said at least one laser beam onmultiple portions of the predetermined areas and partially superimposinga predetermined number of adjacent parts of the multiple portions. 7.The method according to claim 1, further comprising using a pulsed laserbeam.
 8. The method according to claim 7 further comprising setting atleast one parameter selected from the group consisting of: the power ofthe laser radiation, the frequency of the pulses of said pulsed laserradiation, and the trajectory of the movement of the laser beam alongthe surface of the electric conductor.
 9. The method according to claim1, further comprising radiating irradiating the surface of the electricconductor with said at least one laser beam during a bending stage forforming the head portion of the coil member.
 10. The method according toclaim 1, further comprising moving means for generating the laser beamduring the feeding of the electric conductor.
 11. The method accordingto claim 1, further comprising: bending the leg portions extending fromthe stator for positioning predetermined ends of the leg portions inpositions adjacent one to the other; and joining the adjacent legportions.
 12. Apparatus for manufacturing a stator of a dynamo-electricmachine, said apparatus comprising: a coil member former configured tobend an electrical conductor externally coated with an outer insulation,wherein the coil member former bends the electrical conductor atpredetermined lengths from a reference position, wherein a coil member,when formed, comprises at least one head portion and leg portionsextending from said at least one head portion; a feeder configured tofeed the electrical conductor to the coil member former; at least onerespective laser configured to generate a respective laser beam whichirradiates the surface of the electrical conductor to remove theinsulation from predetermined areas of the electrical conductor, whereinsaid laser is situated at a predetermined position with respect to thereference position along the length of the electrical conductor beingfed; a controller configured to control the at least one laser so thatthe irradiating occurs at a predetermined stage of the bending of thecoil member; a cutter configured to cut the electrical conductor so asto detach a formed coil member from said electric conductor; and aninserter configured to insert the leg portions of the coil members inslots of the stator, so that parts of said leg portions extend from anend of the stator and the head portions extend from an opposite end ofthe stator.
 13. The apparatus according to claim 12, wherein thecontroller is further configured to: control the at least one respectivelaser so that said respective laser beam irradiates multiple zones ofthe predetermined areas by moving said laser beam with a predeterminedmovement; and synchronize the movement of said respective laser beamwith the feeding movement of the electrical conductor.
 14. The apparatusaccording to claim 13, wherein the controller is further configured tosum the speed of the movement of the respective laser beam to the speedof the movement of the feeding of the electrical conductor.
 15. Theapparatus according to claim 12, wherein said at least one respectivelaser is positioned at a predetermined distance from the referenceposition, wherein the predetermined distance is an integer multiple ofthe length of the electrical conductor required to form a coil member.16. The apparatus according to claim 12, wherein said at least onerespective laser is configured to emit two laser beams radiated alongthe electrical conductor, wherein a width side and a height side of theelectrical conductor are irradiated by one of said laser beams, and asecond width side and a second height side of the electrical conductorare irradiated by the other one of said laser beams.
 17. The apparatusaccording to claim 12, wherein the controller is further configured tocontrol said respective laser beam to irradiate multiple portions of thepredetermined areas, and to partially superimpose a predetermined numberof adjacent parts of the multiple portions.
 18. The apparatus accordingto claim 12, wherein said at least one respective laser is configuredfor emitting said respective laser beam in a pulsed manner.
 19. Theapparatus according to claim 12, wherein the controller is furtherconfigured to set at least one parameter selected from the groupconsisting of: the power of the laser radiation, the frequency of thepulses of the pulsed laser radiation, and the trajectory of the movementof said respective laser beam along the surface of the electricalconductor.
 20. The apparatus according to claim 12, wherein thecontroller is further configured to make said at least one respectivelaser irradiate the surface of the electrical conductor with saidrespective laser beam during a bending stage for forming the headportion of the coil member.
 21. The apparatus according to claim 12,further comprising: a bender configured to bend the leg portionsextending from the stator for positioning predetermined ends of the legportions adjacent one to the other; and a joiner configured to join theadjacent leg portions.
 22. The apparatus according to claim 12, furthercomprising a mover configured to move the at least one laser during thefeeding of the electrical conductor.